Details and instructions on the monthly timeseries creation webpage

Page will time series of selected pressure level variables from different reanalysis datasets. Select desired options and hit "create plot". Most
options have a default setting so a selection is not required. If you have problems, please email with ALL the options you chose.
You will get a plot as well as the data used to create the final plot (in netCDF), a post script image and information on
the dataset.

Access is proved to various global reanalyses are available. Currently, just pressure level data is available (at the following common levels: 1000., 850.,700.,600.,500.,400.,300.,250.,200.,150.,100. mb. Note that the MERRA dataset is not defined for values below the surface. The MERRA timeseries are created using OPeNDAP access and is often not available.

The following monthly variables are available for each of the reanalyses for the time period of each reanalysis: Geopotential Height, Zonal Wind, Meridional Wind, Air Temperature, Specific Humidity and Relative Humidity. All variables are converted so that they are in the same units.

You can select a second datasets/variable. If you select a 2nd variable, you must select a second dataset. If you choose a second dataset, the default is 1000mb Geopotential Height. If you choose second variable, you can plot the difference between the 2 datasets, plot them on the same time plot, plot a scatter plot or plot a cross-correlation. The correlation and RMS difference will be returned as well as individual statistics on the processed dataset. You cannot plot 12 distributions.

The following monthly variables are available for each of the reanalyses for the time period of each reanalysis: Geopotential Height, Zonal Wind, Meridional Wind, Air Temperature, Specific Humidity and Relative Humidity. All variables are converted so that they are in the same units.

You can choose to use the original monthly averages or you can create your own season. If you choose season, enter your starting and ending month for the season. The year of a season that extends over December is the year of the second month. Seasonal values are created by averaging monthly means or monthly anomalies.

Selecting plot will plot the actual timeseries. For 2 plots, you will get both on the same axis. Difference will plot the difference between a variable from 2 models. For all selections of a second dataset, you will also have
returned the correlation and the RMS difference. For anomalies, the correlation and RMS will be of the anomalies.

Time series can be plotted as a line plot or a bar chart. You can also plot a (single) distribution, a cross-correlation plot for 2 variables (if the are the same, it is an autocorrelation) and a scatter plot.For distributions,you will get a PDF plot based on 15 bins. Keep in mind the number of years you select as well as the issue of a seasonal cycle when selecting distributions.

Selecting "smoothed" will cause a running mean filter to be applied to input timeseries. For monthly data, the smoothing is in months and for season, the smoothing is number of years. The same smoother is applied to 2 timeseries if you choose 2.

Date bounds can be adjusted by entering the year range from low to high. This does not change the analysis. Values are calculated using the years in the input date range near the top of the page. It jut affects how the plot is plotted and can be useful for matching other plots.

The main interface for this page is an html form. The
data that are input into this form are processed by a Perl script.
The script reads the inputs, tests for bad inputs and then NCL
is run to read, analyze and plot the data. NetCDF and postscript are also produced.
The netCDF file, image and other files are kept in a directory
in which the files are periodically deleted.

Please let me know if find the page useful. Likewise,
let me know if you think any instructions are unclear, if you think
there are bugs or if you have any suggestions for improvements of
any type. I would particularly like to know if you use these pages
for teaching purposes and if so, how. I can be reached by email at
cathy.smith@noaa.gov or by phone
at (303) 497-6263.